1. Technical Field
The present invention generally relates to analysis of geographic features and characteristics, and in particular to a system and method for performing flood zone determinations.
2. Description of the Related Art
Today, before a real property is bought, sold, or insured, it is common practice to examine the property for the risk of flooding. This is commonly done by examining the flood zone the property falls into based on its location and elevation. The Federal Emergency management Agency (FEMA) publishes a library of tens of thousands of paper maps showing various types of flood zones and their location in the United States. A flood zone determination on a property is frequently done in the following way.
1. The address of the property is examined, and the location of the property is determined (perhaps through the use of a geocoding system, or by examining an available street map).
2. A map analyst attempts to determine which of the many thousands of FEMA flood maps will contain this property.
3. The map analyst goes to a map storage area and retrieves the desired map, often examining several maps before making a final decision.
4. Having retrieved the paper map, the map analyst next determines where, precisely, the property is located on the map.
5. Finally, the map analyst examines flood zone notations on the map at the property""s location in order to determine its flood zone status.
This process can be somewhat improved by scanning the paper FEMA maps into a computer to produce a digital raster map, which can be retrieved and viewed as necessary. A digital raster map is a computerized map image that resembles a conventional paper map in that it presents an image of the mapped area, but has no additional underlying data associated with the features of the map. A raster map is typically created by scanning a conventional paper map, and is a grid-based map composed of pixels (or dots) of color or black and white. Each pixel in the grid can be referenced by the pixel coordinates, and has only one associated value, indicating the color of that pixel. Raster images are commonly referred to as xe2x80x9cbit mappedxe2x80x9d images.
A vector map uses lines and polygons, rather than pixels, to describe an image. Unlike a raster map, in which the map image is simply stored as a grid of pixels, when a vector map is displayed, it is drawn from a set of underlying data. The vector map is created through the placements of nodes on a plane and connecting those nodes with lines. Vector lines can be attributed with tables of data such as elevations, values, names or other information relative to the line. Vector data can be displayed in three dimensions if the lines are attributed with z values, modified or changed relative to user need, or layered to allow for turning off and on the viewing of different information.
Because of their feature attribution properties, vector maps are particularly useful for displaying geographic data. Vector maps are used to display boundaries or lines that denote the position and extent of features, such as county boundaries or lines denoting stream and river systems. It is also very easy to view or manipulate the data underlying a vector map, for example to view or change the elevation of a feature.
Also, because vector maps are drawn from a data set which describes the locations of features shown, they are often inherently georeferenced. Georeferencing is the process of relating source coordinates to referenced geographic coordinates, which are typically in standard latitude/longitude. An image or a vector file is georeferenced to be used within a mapping/geographic environment. In a vector map, the data from which the map is drawn will typically already include a geographic coordinate set.
Modern GIS systems normally make use of digital vector-based map information. However, a vast legacy of paper-based map information exists. It is very expensive and time consuming to convert all of the information on these paper maps over to a digital vector format. In many cases the scope and expense of such conversions render them completely impractical. However, even when a complete conversion to digital vector-based format is not possible, it is still possible to obtain some of the benefits of computerized map systems, first by converting the paper maps to digital raster maps (by scanning them), and then by georeferencing the raster image. After georeferencing, there should be a clear relationship between the pixel coordinates in the raster map, and the geographic coordinates of the feature represented by that pixel.
Since floodzone determinations are typically performed using paper FEMA maps, it would be desirable to provide a system and method for performing flood zone certifications that is faster and can be performed less expensively than the process described above.
It is therefore one object of the present invention to provide an improved method for analysis of geographic features and characteristics.
It is another object of the present invention to provide an improved system and method for performing flood zone determinations.
The foregoing objects are achieved as is now described. The preferred embodiment provides a system and method for performing flood zone determinations using scanned, georeferenced, digital raster map images. The user, to determine the flood zone classification of a particular property, first enters the street address, or full legal address, into a data processing system. The system determines, from the address, which raster map includes that particular property. The system retrieves that map, and utilizes georeferencing information to locate the property on the raster map. The user can visually verify the location of the property as marked on the displayed raster map, and can at that point examine the flood zone indications on the raster map. Further, the system can compare the geographic coordinates of the property against a database of flood zone boundaries for an automated flood zone determination. The system can also generate, store, and produce flood zone certificates according to the flood zone determination.
The above as well as additional objectives, features, and advantages of the present invention will become apparent in the following detailed written description.